Thanks for the reply and the most useful details.
I did not reply earlier because I wanted to check things thoroughly
first.
I'm not yet fully through with investigating :-(
The problem appears totally erratically, loading the drivers fails app.
ever second time.
Pls see my comments below.

Invalid wrote:

>> Since some weeks when I boot my tc1100 (running under Vista Business
>> 32) I get an error message telling me that the "Tablet driver" was
>> not loaded.
>> Obviously this refers to the Wacom driver.
>>
>> Consequently the "Pen Tablet properties" applet in the Control Panel
>> is not functional.
>>
>> I re-installed the Wacom drivers downloaded from their Website
>> several times.
>> Thereafter things are OK but after some re-boots the problem appears
>> again.
>>
>> Anybody any idea in how to cure the problem and make the newly
>> installed drivers persistent?
>>
>> Unfortunately there is no Restore Point reached back long enough.
>> And I have been really lazy in creating system images :-( :-(
>
> I don't know if this will help. Your comment about the latest Wacom
> drivers reminded me. After installing the Wacom drivers under XP. I
> got a pop-up error message about 10-15 seconds after logging in that
> said
>
> Tablet Driver
> The tablet driver is not running
> and with an OK button

That's what I get as an error message.

> Clicking the OK button cleared the error message, and the Tablet
> drivers all seemed to work fine.

The tablet-things work fine. But the "Pen Tablet Properties" applet
("Pen_Tablet.cpl) in the Control Panel does not work and when calling it
two error messages appear telling that the "Tablet Driver" was not
loaded.

> I finally traced the error message
> to a program in the (all users) Start-up folder called TabUserW.exe.
> This is apparently a Wacom program that allows multiple users to have
> different tablet functionality. Preventing the program from starting
> (msconfig) stopped the error messages appearing without any apparent
> loss of functionality from the Tablet.

The equivalent seems to be "Pen_TabletUser.exe" in
"%SystemRoot%\system32\WTablet\"
There is no item in the Start Menu, however.
And I cannot detect anything pen-/tablet-related which should be loaded
during the startup except "TabletInputService" (MS) and
"TabletServicePen" (named in MS Config). They both appear in the
TaskManager under Services as running.

> However I don't appear to have a copy in my Vista install. That may be
> because I only have a single user account on the Vista install, while
> the XP install ( the machine dual boots) has several user identities.
> Perhaps the Wacom installer detects the number of user accounts ?

AFAICS the situation is independent from the number of accounts.

> If you have the same program try stopping it. It lives in
> Windows/System32/WTablet/

AFAICS this file needs to be loaded as well as
"%SystemRoot\system32\Pen_Tablet.exe".
They appear in the TaskManager as running "Processes" when the system
boots error free. They are missing when the system came up with the
error.

I'm really clueless on what might be wrong and why the problem started
to appear a few weeks ago whereas everything had been fine since the
first install of Vista.
And I have no idea on what to do to fix things.

Rainald